The gas in our intestines comes from several
sources: air we swallow, gas seeping into our intestines from our blood, gas
produced by chemical reactions in our guts, and gas produced by bacteria
living in our guts.

The composition of fart gas is highly variable.
Most of the air we swallow, especially the oxygen component, is absorbed
by the body before the gas gets into the intestines. By the time the air
reaches the large intestine, most of what is left is nitrogen. Chemical
reactions between stomach acid and intestinal fluids may produce carbon
dioxide, which is also a component of air and a product of bacterial action.
Bacteria also produce hydrogen and methane.
But the relative proportions of these gases that emerge from our anal
opening depend on several factors: what we ate, how much air we swallowed,
what kinds of bacteria we have in our intestines, and how long we hold in
the fart.
The longer a fart is held in, the larger the proportion of boring, inert
nitrogen it contains, because the other gases tend to be absorbed into the
bloodstream through the walls of the intestine.
A nervous person who swallows a lot of air and who moves stuff through
his digestive system rapidly may have a lot of oxygen in his farts, because
his body didn't have time to absorb the oxygen. Encyclopaedia Britannica
offers the intriguing statement that some people's farts contain no methane.
The reason for this is apparently unknown. Some researchers suspect a
genetic influence, whereas others think the anomaly is due to environmental
factors. However, all methane in any farts comes from bacterial action and
not from human cells.

The odor of farts comes from small amounts of
hydrogen sulfide gas and skatole in the mixture. These compounds contain
sulfur. The more sulfur-rich your diet, the more sulfides and skatole will
be produced by the bacteria in your guts, and the more your farts will
stink. Foods such as cauliflower, eggs and meat are notorious for producing
smelly farts, whereas beans produce large amounts of not particularly stinky
farts.

On average, a person produces about half a liter of
fart gas per day, distributed over an average of about fourteen daily farts.
Whereas it may be difficult for you to determine your daily flatus
volume, you can certainly keep track of your daily numerical fart count. You
might try this as a science fair project: Keep a journal of everything you
eat and a count of your farts. You might make a note of the potency of their
odor as well. See if you can discover a relationship between what you eat,
how much you fart, and how much they smell.

One may wonder why fart gas travels downward
toward the anus when gas has a lower density than liquids and solids, and
should therefore travel upwards.
The intestine squeezes its contents toward the anus in a series of
contractions, a process called peristalsis. The process is stimulated by
eating, which is why we often need to poop and fart right after a meal.
Peristalsis creates a zone of high pressure, forcing all intestinal
contents, gas included, to move towards a region of lower pressure, which is
toward the anus. Gas is more mobile than other components, and small bubbles
coalesce to from larger bubbles en route to the exit. When peristalsis is
not active, gas bubbles may begin to percolate upwards again, but they won't
get very far due to the complicated and convoluted shape of the intestine.
Furthermore, the anus is neither up nor down when a person is lying down.

Fart travel time depends on atmospheric
conditions such as humidity and wind speed, as well as the distance between
the fart transmitter and the fart receiver. Farts also disperse
as they leave the source, and their potency diminishes with dilution.
Generally, if the fart is not detected within a few seconds, it will be too
dilute for perception and will be lost into the atmosphere forever.
Exceptional conditions exist when the fart is released into a small
enclosed area such as an elevator, a small room, or a car. These conditions
limit the amount of dilution possible, and the fart may remain in a
smellable concentration for a long period of time, until it condenses on the
walls.

No, women fart just as much as men. It's just
that most men take more pride in it than most women. There is a large
variation among individuals in the amount of fart gas produced per day, but
the variation does not correlate with gender.
I have read that men fart more often than women. If this is true,
then women must be saving it up and expelling more gas per fart than men do.

A gentleman is mostly likely to fart first thing
in the morning, while in the bathroom. This is known as "morning thunder,"
and if the gentleman gets good resonance, it can be heard throughout the
household.

Beans contain sugars that we humans cannot digest.
When these sugars reach our intestines, the bacteria go wild, have a big
feast, and make lots of gas!
Other notorious fart-producing foods include corn, bell peppers,
cabbage, milk, and raisins.
A friend of mine had a dog who was exceptionally fond of apples and
turnips. The dog would eat these things and then get prodigious gas. A dog's
digestive system is not equipped to handle such vegetable matter, so the
dog's bacteria worked overtime to produce remarkable flatulence.

People who swallow a lot of air fart more than
people who don't. This can be cured somewhat by chewing with your mouth
closed. Nervous people with fast moving bowels will fart more because less
air is absorbed out of the intestines. Some disease conditions can cause
excess flatulence. And going up in an airplane or other low-pressure
environment can cause the gas inside you to expand and emerge as flatulence.

There are differences in opinion on this one.
Certainly, people have believed for centuries that retaining flatulence is
bad for the health. Emperor Claudius even passed a law legalizing farting at
banquets out of concern for peoples' health. There was a widespread belief
that a person could be poisoned or catch a disease by retaining farts.
Doctors I have spoken to recently have told me that there is no
particular harm in holding in farts. Farts will not poison you; they are a
natural component of your intestinal contents. The worst thing that can
happen is that you may get a stomach ache from the gas pressure. But one
doctor suggested that pathological distention of the bowel could result if a
person holds in farts too much.

As I understand it, a captive fart can escape as
soon as the person relaxes. This means that a lot of people who assiduously
refrain from farting during the day do so at great length as soon as they
fall asleep. Having been on a great many overnight field trips, long bus
trips, and trans-Pacific flights, I can personally vouch for the fact that
lots of people do fart voluminously as they doze off. So the answer to the
question would be, you can refrain from farting as long as you can stay
awake!

How often have you held in a fart, intending to
release it at the first appropriate opportunity, only to find that the fart
has disappeared when you are ready for it?
I asked several doctors where the fart goes. Does it leak out slowly
without the person knowing it? Is it absorbed into the bloodstream? What
happens to it?
The doctors agree that the fart is neither released nor absorbed. It
simply migrates back upward into the intestine and comes out later.
It is reassuring to know that such farts aren't really lost, just
delayed.

The answer to that is yes! However, you should be
aware that people get injured igniting flatulence. Not only can the flame
back up into your colon, but your clothing or other surroundings may catch
on fire. A survey done by Fartcloud indicates
that about a quarter of the people who ignited their farts got burned doing
it. Ignition of flatulence is a hazardous practice.
There have also been cases in which intestinal gases with a higher than
normal oxygen content have exploded during surgery when electric cautery was
used by the surgeon.

No, even strike-anywhere matches have their
limits, unless the fart has the consistency of sandpaper! Any fart that
rough I would hesitate to call a fart. Also, farts have the same temperature
as the body from which they emerge, and aren't hot enough to initiate
combustion.

Few people earn their living directly via
flatulence. But a friend of mine says that he saw a carnival act in which
the performer whistled tunes with his farts, blew out candles on the
opposite side of the stage, and sent flames all the way across the stage. A
famous performer who earned his living this way was Le Petomane, who
performed in France at the beginning of the 20th Century. However, my friend
isn't old enough to have seen Le Petomane, so maybe he had a chance to see
Mr. Methane.
Mr. Methane lays claim to the distinction of being the world's only
performing flatulist.
However, people may also earn a living through the prevention of
flatulence , through the practice of medicine specializing in the treatment of
flatulence and other gastrointestinal problems, by writing books about
flatulence , and through the production
and sales of various fart gags such as whoopee cushions and farts in a can.
Fartypants sells a fart filter and a number of other fart-related
products.
Maybe, if you're lucky, you'll be able to find a copy of Le Petomane's
biography by searching at alibris by clicking on the link below. Last time I
checked, they had two copies available!

A carnivore's protein-rich diet produces relatively
small amounts of intensely stinky gas because proteins contain lots of
sulfur. A dog's or cat's farts are rarely audible, but the odor is
overwhelming. I have asked biologists why dogs and cats generally fart
silently, and their theories include: the amount of gas produced is
small, but potent, the horizontal orientation of their gastrointestinal
system puts less pressure on the anal opening, so the gas is expelled more
slowly, their anal sphincters don't close as tightly as humans' because
it takes less force to hold in the contents of the colon -- again because of
the horizontal orientation of the gastrointestinal system -- and a loose
anus makes less sound, and, my favorite dogs and cats don't feel
embarrassed about farting, so their sphincters are more relaxed, leading to
less noisy flatulence.
Mike F. points out that many dog foods are soy-based, so on top of all
the above factors, add beans and stand back!
Large herbivorous animals such as cows, horses and elephants, on the
other hand, produce vast quantities of relatively non-stinky fart gas. The
farts of these animals are noisy and can go on for astoundingly long periods
of time. Cows in particular are productive, in part because they swallow
huge amounts of air. They need oxygen in their guts for the various protozoa
employed there as digestive aids.

According to our ichthyologist at the University of
Guam, fish flatulence per se has not been studied, although people have
investigated fish digestion. They find that although most fish have alkaline
intestinal environments like our own, coral-eating fish have acidic
intestinal contents. The acid serves to dissolve coral skeletal material.
Coral has the same composition as Tums . One product of
the reaction between acid and calcium carbonate is carbon dioxide gas.
Therefore, it is logical to assume that coral-eating fish fart a lot.
The other fish probably fart also, for the same reasons that we do.
However, Mike Pulte, a great fish enthusiast, said that he has never
seen a fish do it.
I asked our ichthyologist if it were possible that fish gas would go
into the swim bladder instead of out the anal opening. He said that modern
fish have an air bladder that is independent of the gastrointestinal tract.
The gas comes from enzymatic activity and not from the intestine. Older
models of fish have their swim bladder connected to the gastrointestinal
tract, but it is attached high up, closer to the mouth than to the other
end, and these fish come to the surface and gulp air to fill the bladder.
Therefore, we can assume that intestinal gas leaves the fish through the
anal opening.
We also pondered the possibility of fish making noise via flatulence,
but apparently most fish noises are made through belching rather than
farting.
Lisa P., an aquarium enthusiast, reports that she has seen her
fish fart: "I have four aquariums and many fish, and I have personally
witnessed fish farting! My goldfish used to do it all the time! You'd see a
little bubble come out of his anus and stay there, trapped in the mucus of a
long string of poop. And my opaline gourami does it too. Neither of
these are coral-eating fish. I have only owned two coral-eating fish so far,
but I have never seen either of them fart. It seems most likely to me that
much of this gas comes from air swallowed during eating. Also, goldfish have
a very simple digestive system and their food is absorbed inefficiently, so
possibly the bacteria have more to feed on?"

Yes, turtles do fart, and their farts
smell incredibly bad, as do the farts of snakes. In fact, it is my opinion,
based on personal experience with reptiles and not on any formal research,
that many reptiles use farts as a weapon.
Reptile farts smell so bad that sometimes you can tell that one is
nearby in the woods, even on a windy day, before you can see the animal. One
day I was hiking through the woods in Arkansas with a friend and I told my
friend, "I smell a snake fart." A second later, the snake crawled across the
path. Astounding but true!

Believe it or not, the animal that wins this honor
is the humble termite. Because of their diet and digestive processes , they produce as much methane as
human industry. Termite farts are believed to be a major contributor towards
global warming.

If we define a fart to be an anal escape of
intestinal gas, then it follows that animals that lack intestines or an anus
cannot fart. Most animals possess intestines and an anus, but there are
some that don't. These include:
Sponges: These organisms lack true tissues and organs. They have just a
few types of cells organized into a bag with holes in it. Water flows into
some holes and out other holes. Sponges are so different from other animals
that some biologists think we shouldn't even call them animals.
Cnidaria: This phylum includes the jellyfish, corals, sea anemones and
hydra. Their tissues are organized into a bag with a mouth surrounded by
stinging tentacles. Food enters the mouth and is digested inside the bag,
after which the leftovers are expelled via the same opening. In effect, the
same hole serves as both a mouth and an anus. Any gas expelled by a
cnidarian would be more appropriately termed a belch rather than a fart,
since the animal lacks intestines and separate anus.
Pogonophoran worms: These remarkable animals, who dwell on the sea floor
near active volcanic regions associated with mid-ocean ridges, possess no
mouth, no stomach, no intestines, and no anus. Apparently they retain their
svelte, worm-shaped figures by giving up on eating completely! They survive
by means of a mutualistic relationship with chemosynthetic bacteria that
live in their flesh. Anyway, these animals cannot possibly fart.

A second category of animals that probably don't
fart are animals that live very deep underwater. At high pressures, gas
remains in solution rather than forming bubbles. So there is a good chance
that all those clams, echinoderms, fish and other animals living near the
sealer don't fart because their farts stay in solution and never emerge as
bubbles, even though the animals possess perfectly good intestines and
anuses.

Judging from what I see when I do the laundry, I'd
say that the answer to the first question is definitely yes.
As for the causes, we must remember that what we call "fart" and what we
call "poop" are just end-members of a continuum. That is, we can have a pure
fart, or a pure poop, or anything in-between, depending upon the admixture
of the two.
If a sample consists mostly of poop with only a small fart component, you
get such things as jet-propelled bowel movements and spongy, floating fecal
masses .
If the sample consists mostly of fart with only a small poop component,
you get what is known as "skid marks" or "fart art." These can also result
from inadequate wiping, but the shape of the stain is different in the two
cases. Inadequate wiping leads to elongate marks parallel to one's crack,
usually with well-defined edges, whereas fart art is generally more circular
and has an air-brushed look.
Fart art is most likely to occur if a person is suffering from
diarrhea, the person is trying too hard to fart, and the person
mistakenly perceives the pressure against his sphincter to be gas pressure
rather than liquid pressure. Again, that last situation is most likely to
occur if the person is afflicted with diarrhea.

Our ability to distinguish between the need to
fart and the need to poop is something that we learn gradually in the
process of toilet training and early childhood. With the tactile nerve
endings in the rectal area, we can actually feel different sensations
depending upon what is waiting by the exit. Of course, sometimes we are
fooled, especially if the substance at hand is extremely fluid in nature,
and that is when we have the unfortunate accident of venting a squirt of
diarrhea rather than an innocent fart.

I suppose I should start by saying that only
some chicks deny farting. The rest of us acknowledge our gaseous
accomplishments with pride.
However, a great many sisters do deny farting. The reason is that they
have been misled into thinking that farts are not ladylike. It is a great
mistake to say that farting is not ladylike. The reason is that all people
fart, including ladies. Anything that ladies do is by definition ladylike,
and that includes the emission of anal gases.

No, inhaled farts would go into the lungs rather
than into the digestive system, and would simply be exhaled again, although
it might be possible that some of the fart components might be absorbed into
the blood. If you wanted to benefit from other people's farts in the way you
describe, you would have to swallow them somehow.

I am not aware of any intoxicating agents in
flatulence. However, most farts contain very little oxygen, and you may
experience dizziness if you are inhaling overly concentrated fart essence,
simply from lack of oxygen. On the other hand, if you are inhaling farts in
the open air and are breathing rapidly in order to inhale as much fart as
possible, you may be hyperventilating, which also induces dizziness.

Then there is the intrinsic hilarity factor:
farts are so funny in both sound and odor that you might feel high just from
the basic entertainment value of farts.

A great many of you have asked if farts can be
fatal, or if you can die from smelling a particularly bad fart. My initial
response to this question was "no," but I thought I'd better ask a doctor.
So now it is official, the medical opinion I received is no, a fart can't
kill you.
However, if you really work hard at it, you can manage to kill yourself
with just about anything. I recently read of a man who hooked up his nose to
his anus with a system involving a gas mask, rubber tubing and a hollow
wooden post. He died of suffocation. This story comes from the Darwin
Awards, and I personally cannot attest to the overall veracity of their
stories.
The story of the bed-bound obese man who died from inhaling his own
flatulence is an urban legend
that has been in circulation for some time.

That depends on the tolerance level of the person
with whom one is trying to be potent!
Fortunately for humans, farting doesn't cause tissue damage. Other
animals aren't so lucky. Soldier termites can actually turn themselves into
bombs by detonating themselves via the explosive release of gas and feces, a
process called "autothysis."

Yes, but it's a rare talent. The great early 20th
Century French flatulist, Le Petomane, was able to do this, and in fact was
able to suck up an entire bowlful of water
into his colon and expel it again with considerable force. By sucking in
large quantities of air, he was able to perform lengthy shows on stage, and
could imitate musical instruments, farm animals, and bird songs, whistle
melodies, and play the ocarina. His productions were said to be virtually
odorless, which is to be expected from air obtained directly from the
outside.
Here is a message I received recently regarding the
skill of inhaling via the anus:

"i would just like you to know that i am part of a
trio, who can suck in air in our anal openings. we are somewhat air-bandits.
we can let the longest farts you have ever heard. our record holder, chad,
stands at 24 sec. the record for most farts in a row is derek, at 492. and i,
robert, have earned such nicknames as: Mad Crapper, gurglemeister, and old
wetful. We have followed Le Petomane example, and have mastered the art of
farting."

Yes, it is true! The gas that emerges is simply
trapped air, for there is no gas production in the genitalia of a woman. The
air can enter because the system is open to the outside. This highly
specialized kind of fart is sometimes called a queef.

It should be theoretically possible to do this,
but there would be lots of logistical problems. I would suggest using a
plastic bag instead of a jar. You might try the following as a science fair
experiment:
Fart into several plastic bags and seal them carefully. Then fill
several other plastic bags with ordinary air. Wait 24 hours. Then get
volunteers to smell the contents of the bags to see if they can correctly
identify which ones contain the farts. This should tell you if it is
possible to store a fart in any useful way.

Malachi and Megaera have come up with a way to
capture a fart in a jar. They say to do it in the bathtub while bathing.
Fill the jar with bath water and then hold it with the open end downward.
Lean back in the bathtub so that your fart bubbles will emerge in front of
you rather than behind you where you can't see them. Catch the bubbles in
the jar, and put the lid on the jar while it's still underwater. This way,
you capture a fairly pure fart uncontaminated by atmospheric air. To enjoy
your captured fart to the fullest extent, make sure that your jar does not
already smell like whatever was it it before, like pickles or peanut butter.

It is not unusual to enjoy farting. I believe
that enjoyment of farting is a healthy attitude, since everyone has to fart.
If a person is farting to the extent that it creates problems and
unhappiness, then a visit to a doctor is in order.

Farts are, alas, colorless. All of the gases that
make up farts have no inherent color. But just think of how interesting it
would be if farts were bright orange like nitrogen dioxide gas! It would
certainly take the mystery out of who farted.
Never-the-less, a high-personality gas like fart gas suggests color to
people. Some people envision farts as brown, others as green or yellow. I
have always thought of farts as brown, presumably because poop is brown.
When someone farts in our car, that person might say, "You better not
breathe through your mouth for awhile, or your teeth will turn brown."
I knew a toddler who used to draw pictures of farts as yellow rectangles
full of holes, like a slice of Swiss cheese. She thought of farts as yellow,
and said that she knew they were rectangular because she could feel the
sharp corners scraping against her on the way out!

The fart should smell just as much for the person
who created it as it does for other people. However, the farter is somewhat
protected by having the fart propelled away from his body in a direction
opposite to his nose. Farting upwind nullifies this advantage.

As pointed out by Barb F., who contributed the
term listed below, a fart can be regarded as "aerosolized poop," which means
that microscopic fragments and droplets of poop are actually distributed
throughout the gaseous matrix of the fart. When delivered from the anus with
some force, the components of the fart can penetrate one's clothing and
these tiny particles can be trapped in the fibers of the cloth. The
particles are transferred to your fingers and then your nose when you
scratch and sniff.

According to Eric Partridge in his excellent book
of word origins , our word fart comes from the Old English
word feortan, presumably of
echoic origin, meaning that the word was chosen to sound like the object
named.

Now, that's an interesting idea! My guess would
be yes, since farts are nice and moist like our breath, but this is one
question that I'm not in a position to answer. I live in the tropics, and it
never gets cold here. So all of you who live in cold places, try it out and
let me know. I'd guess that there are really two questions here: can you see
the fart with no pants on, and can you see the fart even with pants on...